Detachable cooler for electron tubes



Nov. 1, 1960 YOSUKEI M. MIZUHARA ET'AL 2,958,797

DETACHABLE COOLER FOR ELECTRON TUBES Filed April 24, 1959 2 Sheets-Sheet1 INVENTORS Yosuk M. Mizuhara Mar E. Wolfe 9 1 F W awltyxam Nov. 1, 1960YOSUKE M. MIZUHARA ETAL 2,958,797

DETACHABLE COOLER FOR ELECTRON TUBES Filed April 24, 1959 2 Sheets-Sheet2 INVENTORS Yosuke M. Mizuhara Marf/n E. Wolfe $1M W w fam ATTORNEYSDETACHABLE COOLER FOR ELECTRON TUBES Filed Apr. 24, 1959, Ser. No.808,807

7*Claims. Cl. 313-21 This invention relates to detachable coolers forelectron tubes, and more particularly to a detachable cooler for atraveling wave tube.

As is well known, the anode of certain vacuum tubes and the collector ofbeam type tubes must dissipate large amounts of power. Such power isdissipated in the form of heat making it desirable, and often necessary,to provide cooling for the collector oranode whereby it will not attainexcessive temperatures, and whereby the tube may be operated atrelatively high powers. In the prior art, fin type cooling structureshave been permanently affixed to the tube structure to provide radiationand convection cooling of the anode or collector. Detachable two-piececoolers secured to the tube by means of screws which clamp the sectionsof the cooler against the tube have also been employed in the prior art.

In beam type tubes which are placed in magnetic structures, the fixedcooler is objectionable since the installation of the tube iscomplicated by the fact that an opening must be provided in the magnetfor passing the magnet over the cooling structure or over the electrongun portion of the tube. In either event, an opening of considerablediameter is required and the magnetic structure becomes complicated. Byproviding a magnetic structure which has a small opening, control ofbeam focusing is simplified, the power requirements for the magnet arereduced and the magnetic shielding which need be employed is minimized.

It is a general object of the present invention to provide an improveddetachable cooler for electron tubes.

It is another object of the present invention to provide a detachablecooler having improved thermal and physical contact with the tubestructure.

It is a further object of the present invention to provide a coolerwhich is detachably secured to an associated electron tube by releasablemeans operable from the end of the tube.

It is a further object of the present invention to provide a detachablecooler which is simple in construction, easy to install and remove, andwhich minimizes the opening required in an associated magneticstructure.

The invention possesses other objects and features of advantage, some ofwhich, with the foregoing, will be set forth in the followingdescription of the invention. It is to be understod that the inventionis not to be limited to the disclosed species, as various embodimentsthereof are contemplated and may be adopted within the scope of theclaims.

Referring to the drawing:

Figure 1 is an elevatioual view showing an electron tube incorporating acooler in accordance with the invention;

Figure 2 is an enlarged sectional view of the collector end of thetravelling wave tube of Figure 1; and

Figure 3 is a sectional view taken along the line 3-3 of Figure 2.

The electron tube illustrated in the figures is a travelling wave tubewhich includes an electron gun 11 which tates Patent ice projects anelectron beam axially of the elongated. tube body 12. The beam iscollected by the collector assembly 13. The microwave energy to beamplified is applied through a coaxial connector 14 to one end of thetravelling wave tube helix and is available at the other end of theelectron tube at another coaxial connector 16.

Referring more particularly to Figure 2, a metallic travelling wave tubeenvelope 17 encloses and coaxially supports a helix 18. The helix 18 issupported coaxially by spaced insulating rods 19 which ride on the innersurface of the tube envelope 17. The electron beam is collected by thecollector 22 which comprises a metallic member with an opening 23. Oneend of the opening is disposed on the tube axis to receive the electronbeam. The opening 23 extends at an angle to the axis so that the otherend terminates on an envelope extension 24 which is suitably secured tothe envelope portion 17. The electrons travel into the opening 23,impinge upon .the inclined surface thereof, and are reflected andcollected within the opening 23.

The end of the helix is supported by a dielectric spacer 25 carriedbetween the collector 22 and the envelope extension 24. The end of thehelix is connected to a tapered conductor 27 which extends to the end ofthe envelope extension 24. A dielectric disc 28 carried within the endof the envelope extension 24 forms part of the envelope. The disc 28receives and supports the tubular portion 29 of the inner conductor 30.The tubular portion 29 is sealed to the disc 28. The periphery of thedisc is sealed to the envelope extension 24. Thus, the disc forms partof the evacuated envelope. The inner conductor 30 is supported coaxiallywithin the envelope extension 24 by an insulating sleeve 31. The end ofthe conductor 39 is drilled and slotted to receive the pin of anassociated coaxial line connector. The tapered conductor 27 is connectedto the tubular portion 29 and it forms, in conjunction with the envelopeextension 24 and collector 22, a coaxial transmission line whichprovides suitable impedance transformation between the helix and anassociated coaxial transmission line to minimize reflections.

In accordance with the present invention, a detachable cooler is placedover the tube at the collector end. The cooler is secured to the tube bya wedging action which provides a component contact between the coolerand tube whereby heat is efiiciently conducted away from the collectorto the fin structure 33. The fin structure 33 forms part of a sleeve 34which has a tapered bore 36. As illustrated, the fin structure comprisesa plurality of discs formed as part of the sleeve 34. Cooling air isdirected transverse of the electron tube to provide convective coolingof the discs. It is apparent that the fins may be in the form oflongitudinal ribs which extend radially outward from the sleeve. Coolingair is directed longitudinally of the tube to provide convective coolingof the ribs. The former is the preferred embodiment.

A member 38 is adapted to surround and form physical contact with theelectron tube. The member 38 is wedged between the sleeve 34 and theassociated electron tube to provide good physical, thermal andelectrical contact. The member 38 comprises a tapered portion whichincludes a plurality of longitudinal slots 39 (Figure 3) and a threadedend portion 40 which is adapted to receive the securing nut 41 and theconnector of an associated coaxial transmission line (not shown).

By tightening the nut -41, the member 38 and nut 41 are movedlongitudinally with respect to one another whereby the member 38 iswedged between the sleeve 34 and the wall 24 of the electron tube. Arelatively tight fit is made between the various parts. Preferably, thefin structure is made of aluminum, the tapered memher 38 is made ofbrass and the walls of the electron tube are made of molybdenum wherebythe various parts do not have a tendency to freeze.

To remove the cooling fin structure, the nut 41 is removed and the finassembly moved back towards the end of the tube. The fin assembly isthen removed and its bore is such that it passes over the threadedportion 40 of the member 3%. After the fin structure is removed, thetapered member may be removed.

With the cooling assembly removed, a magnetic structure which fits closeto the wall 17 of the electron tube may be mounted on the tube. Thetapered and slotted member 38 is then placed on the tube and may beadapted to abut against the magnetic structure. The internally taperedsleeve including the fin assembly is then slipped onto the member 38 andthe nut 41 is threaded onto the threaded portion 40. The parts are movedlongitudinally with respect to one another under the forces caused bythreading the nut onto the portion '40 whereby the member 38 is wedgedbetween the sleeve 34 and the electron tube wall 1'7.

It is seen that a cooler which is easily mounted and dismounted from anelectron tube is provided. The 'cooler is simple to install, easy tomanipulate, and provides good thermal and electrical contact to the tubeenvelope.

We claim:

1. A cooler for an electron tube comprising a tapered longitudinallyslotted member adapted to engage said tube, a cooling fin assemblyincluding a sleeve having an internally tapered bore adapted to receivesaid tapered member, and means for moving said sleeve longitudinallywith respect to said tapered slotted member whereby said tapered slottedmember is wedged between the tube and the sleeve.

2. A cooler for an electron tube comprising a tapered longitudinallyslotted member adapted to engage said tube, said tapered slotted memberbeing threaded at its small end, a cooler assembly including a sleevehaving a tapered internal bore adapted to receive said tapered slottedmember, and a nut on the threaded end of said tapered slotted memberadjustable to move the sleeve and tapered slotted member longitudinallywith respect to "one another to wedge said tapered slotted memberagainst the tube.

3. A cooler for electron tubes of the type having a smooth metallicenvelope portion, comprising a longitudinally slotted tapered metalmember detachably engageable to said smooth metallic envelope portion,said slotted tapered member being threaded at its small end, a metalcooler including cooling fins and a sleeve having a tapered internalbore adapted to receive said slotted tapered member in wedgingengagement, and a nut operatively interposed between said tapered memberand said sleeve to move the sleeve and slotted tapered memberlongitudinally with respect to one another whereby the slotted member isurged into intimate contact with the metallic envelope portion.

4. A beam type tube including an electron gun serving to project a beamof electrons and a collector disposed to receive said beam, a metallicenvelope portion surrounding the collector, a ceramic disc carried insaid metallic envelope portion, a conductor adapted to connect to tubeelements within the envelope extending through said disc into theevacuated envelope, said conductor having a portion extending outside ofsaid envelope adapted to be connected to the inner conductor of anassociated coaxial transmission line, a longitudinally slotted taperedmember adapted to engage said envelope portion, said slotted taperedmember being threaded at its small end, a cooler having external coolingfins and including a sleeve having a tapered internal bore adapted toreceive the slotted tapered member, and a nut on the thread end ofslotted tapered member and adjustable to engage the sleeve to move thesleeve and slotted tapered member in a direction with respect to oneanother to effect wedging engagement therebetween, said threaded portionadapted to receive the threaded connector of an associated coaxialtransmission line.

5. In a cooler for an electron tube having a smooth exterior envelopeportion, a wedge member including a plurality of circumferentiallyspaced tapered wedge portions, and a heat conducting and dissipatingassembly mounted on said wedge member and movable therealong to decreasethe spacing between said plurality of wedge portions to clamp said wedgeportions to the smooth exterior of an associated envelope portion.

6. The combination according to claim 5, in which said heat conductingand dissipating assembly includes a sleeve wedgingly engageable withsaid tapered wedge portions, and means fixed on the sleeve fordissipating heat therefrom.

7. The combination according to claim 6, in which said means fixed onthe sleeve for dissipating heat therefrom comprises a plurality ofspaced radially extending fins.

References Cited in the file of this patent UNITED STATES PATENTS

